drivers/watchdog/w83697hf_wdt.c

   1 /*
   2  *      w83697hf/hg WDT driver
   3  *
   4  *      (c) Copyright 2006 Samuel Tardieu <sam@rfc1149.net>
   5  *      (c) Copyright 2006 Marcus Junker <junker@anduras.de>
   6  *
   7  *      Based on w83627hf_wdt.c which is based on advantechwdt.c
   8  *      which is based on wdt.c.
   9  *      Original copyright messages:
  10  *
  11  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
  12  *
  13  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  14  *
  15  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  16  *                                              All Rights Reserved.
  17  *
  18  *      This program is free software; you can redistribute it and/or
  19  *      modify it under the terms of the GNU General Public License
  20  *      as published by the Free Software Foundation; either version
  21  *      2 of the License, or (at your option) any later version.
  22  *
  23  *      Neither Marcus Junker nor ANDURAS AG admit liability nor provide
  24  *      warranty for any of this software. This material is provided
  25  *      "AS-IS" and at no charge.
  26  */
  27
  28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30 #include <linux/module.h>
  31 #include <linux/moduleparam.h>
  32 #include <linux/types.h>
  33 #include <linux/miscdevice.h>
  34 #include <linux/watchdog.h>
  35 #include <linux/fs.h>
  36 #include <linux/ioport.h>
  37 #include <linux/notifier.h>
  38 #include <linux/reboot.h>
  39 #include <linux/init.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/io.h>
  42 #include <linux/uaccess.h>
  43
  44
  45 #define WATCHDOG_NAME "w83697hf/hg WDT"
  46 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  47 #define WATCHDOG_EARLY_DISABLE 1        /* Disable until userland kicks in */
  48
  49 static unsigned long wdt_is_open;
  50 static char expect_close;
  51 static DEFINE_SPINLOCK(io_lock);
  52
  53 /* You must set this - there is no sane way to probe for this board. */
  54 static int wdt_io = 0x2e;
  55 module_param(wdt_io, int, 0);
  56 MODULE_PARM_DESC(wdt_io,
  57                 "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
  58
  59 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  60 module_param(timeout, int, 0);
  61 MODULE_PARM_DESC(timeout,
  62         "Watchdog timeout in seconds. 1<= timeout <=255 (default="
  63                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  64
  65 static bool nowayout = WATCHDOG_NOWAYOUT;
  66 module_param(nowayout, bool, 0);
  67 MODULE_PARM_DESC(nowayout,
  68         "Watchdog cannot be stopped once started (default="
  69                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  70
  71 static int early_disable = WATCHDOG_EARLY_DISABLE;
  72 module_param(early_disable, int, 0);
  73 MODULE_PARM_DESC(early_disable,
  74         "Watchdog gets disabled at boot time (default="
  75                                 __MODULE_STRING(WATCHDOG_EARLY_DISABLE) ")");
  76
  77 /*
  78  *      Kernel methods.
  79  */
  80
  81 #define W83697HF_EFER (wdt_io + 0)  /* Extended Function Enable Register */
  82 #define W83697HF_EFIR (wdt_io + 0)  /* Extended Function Index Register
  83                                                         (same as EFER) */
  84 #define W83697HF_EFDR (wdt_io + 1)  /* Extended Function Data Register */
  85
  86 static inline void w83697hf_unlock(void)
  87 {
  88         outb_p(0x87, W83697HF_EFER);    /* Enter extended function mode */
  89         outb_p(0x87, W83697HF_EFER);    /* Again according to manual */
  90 }
  91
  92 static inline void w83697hf_lock(void)
  93 {
  94         outb_p(0xAA, W83697HF_EFER);    /* Leave extended function mode */
  95 }
  96
  97 /*
  98  *      The three functions w83697hf_get_reg(), w83697hf_set_reg() and
  99  *      w83697hf_write_timeout() must be called with the device unlocked.
 100  */
 101
 102 static unsigned char w83697hf_get_reg(unsigned char reg)
 103 {
 104         outb_p(reg, W83697HF_EFIR);
 105         return inb_p(W83697HF_EFDR);
 106 }
 107
 108 static void w83697hf_set_reg(unsigned char reg, unsigned char data)
 109 {
 110         outb_p(reg, W83697HF_EFIR);
 111         outb_p(data, W83697HF_EFDR);
 112 }
 113
 114 static void w83697hf_write_timeout(int timeout)
 115 {
 116         /* Write Timeout counter to CRF4 */
 117         w83697hf_set_reg(0xF4, timeout);
 118 }
 119
 120 static void w83697hf_select_wdt(void)
 121 {
 122         w83697hf_unlock();
 123         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
 124 }
 125
 126 static inline void w83697hf_deselect_wdt(void)
 127 {
 128         w83697hf_lock();
 129 }
 130
 131 static void w83697hf_init(void)
 132 {
 133         unsigned char bbuf;
 134
 135         w83697hf_select_wdt();
 136
 137         bbuf = w83697hf_get_reg(0x29);
 138         bbuf &= ~0x60;
 139         bbuf |= 0x20;
 140
 141         /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
 142         w83697hf_set_reg(0x29, bbuf);
 143
 144         bbuf = w83697hf_get_reg(0xF3);
 145         bbuf &= ~0x04;
 146         w83697hf_set_reg(0xF3, bbuf);   /* Count mode is seconds */
 147
 148         w83697hf_deselect_wdt();
 149 }
 150
 151 static void wdt_ping(void)
 152 {
 153         spin_lock(&io_lock);
 154         w83697hf_select_wdt();
 155
 156         w83697hf_write_timeout(timeout);
 157
 158         w83697hf_deselect_wdt();
 159         spin_unlock(&io_lock);
 160 }
 161
 162 static void wdt_enable(void)
 163 {
 164         spin_lock(&io_lock);
 165         w83697hf_select_wdt();
 166
 167         w83697hf_write_timeout(timeout);
 168         w83697hf_set_reg(0x30, 1);      /* Enable timer */
 169
 170         w83697hf_deselect_wdt();
 171         spin_unlock(&io_lock);
 172 }
 173
 174 static void wdt_disable(void)
 175 {
 176         spin_lock(&io_lock);
 177         w83697hf_select_wdt();
 178
 179         w83697hf_set_reg(0x30, 0);      /* Disable timer */
 180         w83697hf_write_timeout(0);
 181
 182         w83697hf_deselect_wdt();
 183         spin_unlock(&io_lock);
 184 }
 185
 186 static unsigned char wdt_running(void)
 187 {
 188         unsigned char t;
 189
 190         spin_lock(&io_lock);
 191         w83697hf_select_wdt();
 192
 193         t = w83697hf_get_reg(0xF4);     /* Read timer */
 194
 195         w83697hf_deselect_wdt();
 196         spin_unlock(&io_lock);
 197
 198         return t;
 199 }
 200
 201 static int wdt_set_heartbeat(int t)
 202 {
 203         if (t < 1 || t > 255)
 204                 return -EINVAL;
 205
 206         timeout = t;
 207         return 0;
 208 }
 209
 210 static ssize_t wdt_write(struct file *file, const char __user *buf,
 211                                                 size_t count, loff_t *ppos)
 212 {
 213         if (count) {
 214                 if (!nowayout) {
 215                         size_t i;
 216
 217                         expect_close = 0;
 218
 219                         for (i = 0; i != count; i++) {
 220                                 char c;
 221                                 if (get_user(c, buf + i))
 222                                         return -EFAULT;
 223                                 if (c == 'V')
 224                                         expect_close = 42;
 225                         }
 226                 }
 227                 wdt_ping();
 228         }
 229         return count;
 230 }
 231
 232 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 233 {
 234         void __user *argp = (void __user *)arg;
 235         int __user *p = argp;
 236         int new_timeout;
 237         static const struct watchdog_info ident = {
 238                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 239                                                         | WDIOF_MAGICCLOSE,
 240                 .firmware_version = 1,
 241                 .identity = "W83697HF WDT",
 242         };
 243
 244         switch (cmd) {
 245         case WDIOC_GETSUPPORT:
 246                 if (copy_to_user(argp, &ident, sizeof(ident)))
 247                         return -EFAULT;
 248                 break;
 249
 250         case WDIOC_GETSTATUS:
 251         case WDIOC_GETBOOTSTATUS:
 252                 return put_user(0, p);
 253
 254         case WDIOC_SETOPTIONS:
 255         {
 256                 int options, retval = -EINVAL;
 257
 258                 if (get_user(options, p))
 259                         return -EFAULT;
 260
 261                 if (options & WDIOS_DISABLECARD) {
 262                         wdt_disable();
 263                         retval = 0;
 264                 }
 265
 266                 if (options & WDIOS_ENABLECARD) {
 267                         wdt_enable();
 268                         retval = 0;
 269                 }
 270
 271                 return retval;
 272         }
 273
 274         case WDIOC_KEEPALIVE:
 275                 wdt_ping();
 276                 break;
 277
 278         case WDIOC_SETTIMEOUT:
 279                 if (get_user(new_timeout, p))
 280                         return -EFAULT;
 281                 if (wdt_set_heartbeat(new_timeout))
 282                         return -EINVAL;
 283                 wdt_ping();
 284                 /* Fall */
 285
 286         case WDIOC_GETTIMEOUT:
 287                 return put_user(timeout, p);
 288
 289         default:
 290                 return -ENOTTY;
 291         }
 292         return 0;
 293 }
 294
 295 static int wdt_open(struct inode *inode, struct file *file)
 296 {
 297         if (test_and_set_bit(0, &wdt_is_open))
 298                 return -EBUSY;
 299         /*
 300          *      Activate
 301          */
 302
 303         wdt_enable();
 304         return nonseekable_open(inode, file);
 305 }
 306
 307 static int wdt_close(struct inode *inode, struct file *file)
 308 {
 309         if (expect_close == 42)
 310                 wdt_disable();
 311         else {
 312                 pr_crit("Unexpected close, not stopping watchdog!\n");
 313                 wdt_ping();
 314         }
 315         expect_close = 0;
 316         clear_bit(0, &wdt_is_open);
 317         return 0;
 318 }
 319
 320 /*
 321  *      Notifier for system down
 322  */
 323
 324 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 325         void *unused)
 326 {
 327         if (code == SYS_DOWN || code == SYS_HALT)
 328                 wdt_disable();  /* Turn the WDT off */
 329
 330         return NOTIFY_DONE;
 331 }
 332
 333 /*
 334  *      Kernel Interfaces
 335  */
 336
 337 static const struct file_operations wdt_fops = {
 338         .owner          = THIS_MODULE,
 339         .llseek         = no_llseek,
 340         .write          = wdt_write,
 341         .unlocked_ioctl = wdt_ioctl,
 342         .open           = wdt_open,
 343         .release        = wdt_close,
 344 };
 345
 346 static struct miscdevice wdt_miscdev = {
 347         .minor = WATCHDOG_MINOR,
 348         .name = "watchdog",
 349         .fops = &wdt_fops,
 350 };
 351
 352 /*
 353  *      The WDT needs to learn about soft shutdowns in order to
 354  *      turn the timebomb registers off.
 355  */
 356
 357 static struct notifier_block wdt_notifier = {
 358         .notifier_call = wdt_notify_sys,
 359 };
 360
 361 static int w83697hf_check_wdt(void)
 362 {
 363         if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
 364                 pr_err("I/O address 0x%x already in use\n", wdt_io);
 365                 return -EIO;
 366         }
 367
 368         pr_debug("Looking for watchdog at address 0x%x\n", wdt_io);
 369         w83697hf_unlock();
 370         if (w83697hf_get_reg(0x20) == 0x60) {
 371                 pr_info("watchdog found at address 0x%x\n", wdt_io);
 372                 w83697hf_lock();
 373                 return 0;
 374         }
 375         /* Reprotect in case it was a compatible device */
 376         w83697hf_lock();
 377
 378         pr_info("watchdog not found at address 0x%x\n", wdt_io);
 379         release_region(wdt_io, 2);
 380         return -EIO;
 381 }
 382
 383 static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };
 384
 385 static int __init wdt_init(void)
 386 {
 387         int ret, i, found = 0;
 388
 389         pr_info("WDT driver for W83697HF/HG initializing\n");
 390
 391         if (wdt_io == 0) {
 392                 /* we will autodetect the W83697HF/HG watchdog */
 393                 for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
 394                         wdt_io = w83697hf_ioports[i];
 395                         if (!w83697hf_check_wdt())
 396                                 found++;
 397                 }
 398         } else {
 399                 if (!w83697hf_check_wdt())
 400                         found++;
 401         }
 402
 403         if (!found) {
 404                 pr_err("No W83697HF/HG could be found\n");
 405                 ret = -EIO;
 406                 goto out;
 407         }
 408
 409         w83697hf_init();
 410         if (early_disable) {
 411                 if (wdt_running())
 412                         pr_warn("Stopping previously enabled watchdog until userland kicks in\n");
 413                 wdt_disable();
 414         }
 415
 416         if (wdt_set_heartbeat(timeout)) {
 417                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 418                 pr_info("timeout value must be 1 <= timeout <= 255, using %d\n",
 419                         WATCHDOG_TIMEOUT);
 420         }
 421
 422         ret = register_reboot_notifier(&wdt_notifier);
 423         if (ret != 0) {
 424                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
 425                 goto unreg_regions;
 426         }
 427
 428         ret = misc_register(&wdt_miscdev);
 429         if (ret != 0) {
 430                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 431                        WATCHDOG_MINOR, ret);
 432                 goto unreg_reboot;
 433         }
 434
 435         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 436                 timeout, nowayout);
 437
 438 out:
 439         return ret;
 440 unreg_reboot:
 441         unregister_reboot_notifier(&wdt_notifier);
 442 unreg_regions:
 443         release_region(wdt_io, 2);
 444         goto out;
 445 }
 446
 447 static void __exit wdt_exit(void)
 448 {
 449         misc_deregister(&wdt_miscdev);
 450         unregister_reboot_notifier(&wdt_notifier);
 451         release_region(wdt_io, 2);
 452 }
 453
 454 module_init(wdt_init);
 455 module_exit(wdt_exit);
 456
 457 MODULE_LICENSE("GPL");
 458 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, "
 459                 "Samuel Tardieu <sam@rfc1149.net>");
 460 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
 461 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);